Methods used in serving radio node and control node, and associated devices

ABSTRACT

A method used in a serving radio node and an associated serving radio node. The method includes receiving, from a control node controlling the serving radio node, a sounding and sensing related configuration for the serving radio node, wherein each sounding resource element indicated by the sounding and sensing related configuration is orthogonal to each sounding resource element indicated by a sounding and sensing related configuration for each neighboring radio node; and sensing, through a Receiver (RX) Radio Frequency (RF) chain of the serving radio node configured for each radio link of the one or more radio links, all sounding signals in a direction of the radio link based on the received sounding and sensing related configuration. Further methods described are used in a serving radio node, an associated serving radio node, and in a control node to control the serving radio node and the associated control node.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.15/028,620, filed Apr. 11, 2016, which is a National stage ofInternational Application No. PCT/CN2015/082516, filed Jun. 26, 2015,which are all hereby incorporated by reference.

TECHNICAL FIELD

The technology presented in this disclosure generally relates to thetechnical field of wireless communication networks. More particularly,the present disclosure relates to methods used in a serving radio nodeand the associated serving radio node, and to a method used in a controlnode controlling a serving radio node and the associated control node.

BACKGROUND ART

This section is intended to provide a background to the variousembodiments of the technology described in this disclosure. Thedescription in this section may include concepts that could be pursued,but are not necessarily ones that have been previously conceived orpursued. Therefore, unless otherwise indicated herein, what is describedin this section is not prior art to the description and/or claims ofthis disclosure and is not admitted to be prior art by the mereinclusion in this section.

Currently, wireless communication networks or systems, such asMilliMeter-Wave (MMW) wireless systems, operating at high frequenciesfrom 30-300 GHz, are emerging as a promising technology to meetexploding bandwidth requirements by enabling multi-Gb/s speeds. Forexample, the 5th Generation (5G) network is likely to be a combinationof evolved 3rd Generation (3G) technologies, the 4th Generation (4G)technologies and emerging or substantially new components such asUltra-Density Network (UDN), which is also referred to as MMW RadioAccess Technology (RAT). At such high frequencies, a large number ofantennas can be available at a transmitter, a receiver, or both. Inorder to make up for the large propagation loss that typically occurs,beam-forming becomes a very important feature in MMW wireless systems.

Beam-forming is a signal processing technique used for directionalsignal transmission and/or reception. For Transmitter (TX) beamforming,the signals are concentrated in the desired direction via applying aselected precoding vector for the TX antenna array. For Receiver (RX)beamforming, the RX beam of the receiver antennas are concentrated inthe incoming direction of the radio signals by applying a selectedprecoding vector for the RX antenna array. Beam-forming can be used atboth the transmitting and receiving ends in order to achieve spatialselectivity. The improvement compared with omnidirectionalreception/transmission is known as a beam-forming gain. When multipleantennas are available at transmitters, receivers or both, it istherefore important to apply efficient beam patterns to the antennas tobetter exploit the spatial selectivity of the corresponding wirelesschannel.

FIG. 1 schematically shows one example MMW RAT network. As shown in FIG.1, there is a network node or a control node called as Central ControlUnit (CCU), which is at least responsible for parameter configurationsand coordination among Access Nodes (ANs), e.g., AN1, AN2, AN3, and AN4.

Typically, received power in a receiver side can be expressed as:

$P_{rx} = {P_{TX} \cdot G_{TX} \cdot {G_{RX}\left( \frac{r}{4\;\pi\;\lambda} \right)}^{2} \cdot e^{{- \alpha}\; r}}$where P_(TX) is transmitted power, G_(TX) and G_(RX) are beamforminggains of transmitting and receiving antennas, respectively, λ is thewavelength, and α is the attenuation factor due to absorption in themedium. For an MMW-wave link at 60 GHz, oxygen absorption loss can be ashigh as 16 dB/km.

From the above formula, it is clear that the attenuation of radio waveis proportional to 1/λ². With the same propagation distance, 60 GHzattenuates 29.5 dB more compared to 2 GHz, without considering theoxygen absorption.

In considering this, high gain beam-forming is mandatory in order tocompensate the extra attenuation. Thanks to the small wavelength, moreantenna elements can be integrated in the antenna panel with the samesize. This makes it possible to reach a higher beam-forming gain.However, if there are several tens or several hundreds of antennaelements, one Radio Frequency (RF) chain (either TX RF chain or RX RFchain) for each antenna element is inapplicable due to unacceptablecost. In such a case, multiple antenna elements share one RF chain and aspecific analog phase adjustment is applied for each antenna in order toadjust the beam direction and maximize the beam-forming gain. Due to thenarrow TX beam, it is needed to steer transmission of beacon signals toenable AN discovery area, and to preform beam-forming training tomaximize the beam-forming gain.

Meanwhile, high gain beam-forming could bring challenges, including,e.g., hidden problem and deafness problem.

FIG. 2 illustrates an example of the hidden problem caused bydirectivity of high gain beam-forming. As shown in FIG. 2, link pair 1is composed by Access Point 1 (AP1) and User Equipment 1 (UE1), and linkpair 2 is composed by AP2 and UE2. When AP2 is transmitting to UE2,neither AP 1 or UE 1 can detect the channel utilized by AP2 and UE2because both AP1 and UE1 are outside of the TX beam coverage from AP2 toUE2. However, when AP1 transmits data to UE1, its TX beam can reach UE2and cause interference.

FIG. 3 illustrates an example of the deafness problem caused bydirectivity of high gain beam-forming. As shown in FIG. 3, UE 1 and AP1compose link pair 1 and UE2 and AP2 compose link pair 2. The link pair 2has ongoing data transmission from AP2 to UE2. But this is not detectedby UE1 because UE1 does not monitor (or sense) this direction. However,when UE 1 starts data transmission, the data receiving by UE2 can beclearly impacted due to UE1 and UE2 are close to each other.

Currently, it is supposed that the total carrier bandwidth of theMMW-RAT can be up to 1 or 2 GHz. This bandwidth can be composed by anumber of sub-band carriers of a certain bandwidth, e.g. 100 MHz. By wayof example, FIG. 4 illustrates one MMW-RAT carrier with 4 sub-bands. Thesmallest resource grid in FIG. 4 corresponds to a sub-band in thefrequency domain and to a subframe in the time domain, and may bereferred to as a sounding and sensing resource element. Of course, thesounding and sensing resource element may be also in terms of code.

To allocate the available resources, a contention based resourceallocation scheme and/or a scheduling based resource allocation schememay be applied in MMW-RAT as the basic policy of collision avoidance. Acontention based resource allocation scheme provides a mechanism tocompete for the channel based on the self-determination on the channelavailability. In a scheduling based resource allocation scheme, ascheduler, e.g., a CCU as shown in FIG. 1, gains the resourcecontrollability first via either contention based method or coordinationmethod first and allocates the resource to controlled links.

There could be certain combination of the contention based resourceallocation scheme and the scheduling based resource allocation scheme.FIG. 5 illustrates an example of a complex interference situation in aMMW-RAT network. As shown in FIG. 5, due to directivity of high gainbeam-forming, Link 1 and Link 2 may have unendurable UpLink (UL) toDownLink (DL) interference while Link 5 and Link 6 may have unendurableDL to DL interference and UL to DL interference.

Due to directivity of high gain beam-forming, the collisiondetermination is more complex than omni-transmission. The traditionalmeasurement does not work well due to the aforementioned deafness andhidden problems. Besides, though carrier sensing methods commerciallyused in Wireless Local Area Network (WLAN, 802.11) and Wireless PersonalArea Network (WPAN, 802.15) are developed, they are mainly for localaccess system. It is a distributed carrier sensing scheme, i.e., thecarrier sensing is done by each node pair independently. For MMW RAT,firstly it is expected that there can be better dimensioned deploymentinvolving multiple nodes of APs and UEs, and better networkcontrollability (e.g., self-optimization, self-organization, andmobility) than Wireless Fidelity (WiFi) is targeted. Secondly, MMW RATis expected to provide much better Quality of Service (QoS) than WiFi.In this sense, a better measurement than simple distributed carriersensing of WiFi is desired.

The interference measurements in 3G and 4G wireless systems are mainlydesigned to measure the inter-cell/inter-Transmission-Pointinterference, rather than inter-link interference. Due to small sectorsize and the large overlapping coverage in case of MMW RAT, the similarmeasurement as 3G or 4G systems is not enough to identify links incollision and help the interference management.

SUMMARY

It is in view of the above considerations and others that the variousembodiments of the present technology have been made. To be specific,aiming to at least some of the above defects, the present disclosureproposes to configure neighboring radio nodes under control of one CCUwith different sounding and sensing related configurations, therebyfacilitating interference measurements.

According to a first aspect of the present disclosure, there is proposeda method used in a serving radio node. The serving radio node serves oneor more client radio nodes which are connected to the serving radio nodevia one or more radio links, in a coverage area neighboring to one ormore coverage areas served by one or more neighboring radio nodes in awireless communication network. The method includes receiving, from acontrol node controlling the serving radio node, a sounding and sensingrelated configuration for the serving radio node. Each sounding resourceelement indicated by the sounding and sensing related configuration isorthogonal to each sounding resource element indicated by a sounding andsensing related configuration for each neighboring radio node. Themethod further includes sensing, through a RX RF chain of the servingradio node configured for each radio link of the one or more radiolinks, all sounding signals in a direction of the radio link based onthe received sounding and sensing related configuration.

Preferably, the received sounding and sensing related configurationindicates two or more sounding and sensing windows per sounding andsensing duration, one or more sounding and sensing windows of which areconfigured as sensing windows for sensing by the serving radio node, andthe remaining sounding and sensing windows of which are configured assounding windows for sounding by the serving radio node.

Preferably, the sounding windows for the serving radio node correspond,in time domain, to sensing windows for each neighboring radio node.

Preferably, each sounding and sensing window has a same or differentnumber of sounding and sensing resource elements.

Preferably, each sounding and sensing window has consecutive ornon-consecutive sounding and sensing resource elements.

Preferably, the method further includes allocating one or more soundingand sensing resource elements indicated by the received sounding andsensing related configuration, to the one or more radio links.

Preferably, the sensing is performed in all sensing resource elementsindicated by the received sounding and sensing related configuration.

Preferably, the sensing is further performed in a part or all soundingresource elements indicated by the received sounding and sensing relatedconfiguration.

Preferably, the method further includes: adjusting a sensing period foreach radio link of the one or more radio links based on the receivedsounding and sensing related configuration and one or more predefinedparameters, when the number of RX RF chains of the serving radio node issmaller than the number of all radio links for which the serving nodeserves as receivers; sensing, through a RX RF chain of the serving radionode configured for each radio link of the one or more radio links, allsounding signals in a direction of the radio link, based on the adjustedsensing period.

Preferably, the one or more predefined parameters include at least oneof: a link radio quality; a link rate; or a link traffic priority.

According to a second aspect of the present disclosure, there isproposed a method used in a control node controlling a serving radionode. The serving radio node serves one or more client radio nodes whichare connected to the serving radio node via one or more radio links, ina coverage area neighboring to one or more coverage areas served by oneor more neighboring radio nodes in a wireless communication network. Themethod includes: determining a sounding and sensing relatedconfiguration for the serving radio node, wherein the sounding resourceelement indicated by the sounding and sensing related configuration forthe serving radio node is orthogonal to each sounding resource elementindicated by a sounding and sensing related configuration for eachneighboring radio node; and transmitting the determined sounding andsensing related configuration to the serving radio node.

According to a third aspect of the present disclosure, there is proposeda method used in a serving radio node. The serving radio node serves oneor more client radio nodes which are connected to the serving radio nodevia one or more radio links, in a coverage area neighboring to one ormore coverage areas served by one or more neighboring radio nodes in awireless communication network. The method includes: receiving, from acontrol node controlling the serving radio node, a sounding and sensingrelated configuration for the serving radio node; adjusting a sensingperiod for each radio link of the one or more radio links based on thesounding and sensing related configuration and one or more predefinedparameters, when the number of RX RF chains of the serving radio node issmaller than the number of the one or more radio links for which theserving node serves as receivers; and sensing, through a RX RF chain ofthe serving radio node configured for each radio link of the one or moreradio links, all sounding signals in a direction of the radio link,based on the adjusted sensing period.

According to a fourth aspect of the present disclosure, there isproposed a serving radio node, which serves one or more client radionodes which are connected to the serving radio node via one or moreradio links, in a coverage area neighboring to one or more coverageareas served by one or more neighboring radio nodes in a wirelesscommunication network. The serving radio node includes: a receiving unitconfigured to receive, from a control node controlling the serving radionode, a sounding and sensing related configuration for the serving radionode, wherein each sounding resource element indicated by the soundingand sensing related configuration is orthogonal to each soundingresource element indicated by a sounding and sensing relatedconfiguration for each neighboring radio node; and a sensing unitconfigured to sense, through a RX RF chain of the serving radio nodeconfigured for each radio link of the one or more radio links, allsounding signals in a direction of the radio link, based on the receivedsounding and sensing related configuration.

According to a fifth aspect of the present disclosure, there is proposeda control node controlling a serving radio node. The serving radio nodeserves one or more client radio nodes which are connected to the servingradio node via one or more radio links, in a coverage area neighboringto one or more coverage areas served by one or more neighboring radionodes in a wireless communication network. The control node includes: adetermining unit configured to determine a sounding and sensing relatedconfiguration for the serving radio node, wherein the sounding resourceelement indicated by the sounding and sensing related configuration forthe serving radio node is orthogonal to each sounding resource elementindicated by a sounding and sensing related configuration for eachneighboring radio node; and a transmitting unit configured to transmitthe determined sounding and sensing related configuration to the servingradio node.

According to a sixth aspect of the present disclosure, there is proposeda serving radio node, which serves one or more client radio nodes whichare connected to the serving radio node via one or more radio links, ina coverage area neighboring to one or more coverage areas served by oneor more neighboring radio nodes in a wireless communication network. Theserving radio node includes: a receiving unit configured to receive,from a control node controlling the serving radio node, a sounding andsensing related configuration for the serving radio node; an adjustingunit configured to adjust a sensing period for each radio link of theone or more radio links based on the sounding and sensing relatedconfiguration and one or more predefined parameters, when the number ofRX RF chains of the serving radio node is smaller than the number of theone or more radio links for which the serving node serves as receivers;and a sensing unit configured to sense, through a RX RF chain of theserving radio node configured for each radio link of the one or moreradio links, all sounding signals in a direction of the radio link,based on the adjusted sensing period.

According to a seventh aspect of the present disclosure, there isproposed a computer program product storing instructions that whenexecuted, cause one or more computing devices to perform the method ofany of the first to the third aspects.

According to the present disclosure, neighboring radio nodes under thecontrol of one CCU are configured with different sounding and sensingrelated configurations, in such a manner that each sounding resourceelement indicated by one radio node's sounding and sensing relatedconfiguration is orthogonal to each sounding resource element indicatedby a sounding and sensing related configuration for each of itsneighboring radio node. In this case, a TX RF chain of a radio node isconfigured with a resource element for transmitting sounding signals inits link direction, and correspondingly, a RX RF chain of the radionode's neighboring node is configured with the same resource element forsensing (monitoring) all possible sounding signals in its linkdirection. That is, when a radio node is in a directional sounding state(i.e., in TX state), each neighboring radio node should be sensingdirectional sounding signals (i.e., in RX state). This facilitatesinterference measurement, while improving interference measurementaccuracy.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of this disclosure will become morefully apparent from the following description and appended claims, takenin conjunction with the accompanying drawings. Understanding that thesedrawings depict only several embodiments in accordance with thedisclosure and are, therefore, not to be considered limiting of itsscope, the disclosure will be described with additional specificity anddetail through use of the accompanying drawings.

FIG. 1 schematically shows one example MMW RAT network.

FIG. 2 illustrates an example of the hidden problem caused bydirectivity of high gain beam-forming.

FIG. 3 illustrates an example of the deafness problem caused bydirectivity of high gain beam-forming.

FIG. 4 illustrates one MMW-RAT carrier with 4 sub-bands.

FIG. 5 illustrates an example of a complex interference situation in aMMW-RAT network.

FIG. 6 depicts an example of a wireless communication network in whichembodiments herein may be implemented.

FIG. 7 shows a flowchart of a method 700 performed in a control nodeaccording to embodiments of the present disclosure.

FIG. 8 illustrates a general sounding and sensing resource allocationstructure according to embodiments of the present disclosure.

FIG. 9 shows a flowchart of a method 900 performed in a receiving nodeof a link according to embodiments of the present disclosure.

FIG. 10 illustrates an example sensing resource allocation structureaccording to embodiments of the present disclosure.

FIG. 11 shows a flowchart of a method 1100 performed in a transmittingnode of a link according to embodiments of the present disclosure.

FIG. 12 illustrates an example sounding resource allocation structureaccording to embodiments of the present disclosure.

FIG. 13 illustrates three exemplary divisions of DSSI into DSSWsaccording to the present disclosure.

FIG. 14 shows three exemplary DSSI configurations according to thepresent disclosure.

FIG. 15 illustrates two exemplary network deployments under control of aCCU according to the present disclosure.

FIG. 16 shows a flowchart of a method 1600 used in a serving radio nodeaccording to embodiments of the present disclosure.

FIG. 17 illustrates an exemplary DSSI pattern according to embodimentsof the present disclosure.

FIG. 18 shows a flowchart of a method 1800 used in a serving radio nodeaccording to embodiments of the present disclosure.

FIG. 19 shows a flowchart of a method 1900 used in a control nodecontrolling a serving radio node according to embodiments of the presentdisclosure.

FIG. 20 is a schematic block diagram of a serving radio node 2000according to the present disclosure.

FIG. 21 shows a schematic block diagram of another serving radio node2100 according to the present disclosure.

FIG. 22 is a schematic block diagram of a control node 2200 controllinga serving radio node according to embodiments of the present disclosure.

FIG. 23 schematically shows an embodiment of an arrangement 2300 whichmay be used in the serving radio node 2000, the serving radio node 2100,or the control node 2200 according to the present disclosure.

DETAILED DESCRIPTION

Hereinafter, the present disclosure is described with reference toembodiments shown in the attached drawings. However, it is to beunderstood that those descriptions are just provided for illustrativepurpose, rather than limiting the present disclosure. Further, in thefollowing, descriptions of known structures and techniques are omittedso as not to unnecessarily obscure the concept of the presentdisclosure.

First of all, the present disclosure proposes to align directionalsounding and sensing parameters (this solution may be referred to asAligned Directional Sounding and Sensing (ADSS) hereinafter), e.g., inan MMW RAT network. To be specific, the present disclosure configures atransmitter of each link pair (i.e., link transmitter and receiver) witha time-frequency radio resource pattern to send directional soundingbeam in its link direction, and correspondingly configures a receiver ofeach link pair with the same time-frequency radio resource pattern todirectionally monitor all possible sounding signals in its linkdirections. Thereby, receivers of all link pairs may be in a directionalsensing state when their corresponding transmitters are sendingdirectional sounding signals. In this way, the victim link pairs and theinterfering link pairs can be accurately identified and the mutualinterference levels can be measured. That is, an effective inter-linkinterference map (also referred to as Directional Link Interference Map,i.e. DLIM) of an MMW RAT network can be derived. Such measurementinformation can be used to enhance the resource allocation schemes,e.g., time, frequency and transmit power resource.

FIG. 6 depicts an example of a wireless communication network in whichADSS may be implemented. The wireless communication network comprises aCentral Control Unit (CCU) 600 and a plurality of radio nodes (alsoreferred to as access nodes (ANs)) whereof six ANs are depicted in FIG.6. The CCU 600 may be a Node B, a Base Station (BS), an eNB, an eNodeB,an Home Node B, an Home eNodeB, a relay node, an AP or any other controlnode or network node at least responsible for parameter configurationsand coordination among ANs as well as controlling radio links among ANs,in any wireless system or cellular network, such as an LTE network, any3rd Generation Partnership Project (3GPP) cellular network, an MMWnetwork, a Wimax network, a WLAN/Wi-Fi, a WPAN etc. Each radio node maye.g., be a wireless device, a mobile wireless terminal or a wirelessterminal, a mobile phone, a computer such as a laptop, a PersonalDigital Assistants (PDAs) or a tablet computer, sometimes referred to asa phablet, with wireless capability (the foregoing ones may becollectively known as a UE), a sensor or actuator with wirelesscapabilities or any other radio network units capable to communicateover a radio link in a wireless communication network. It should benoted that the term “radio node” or “AN” used in this document alsocovers other wireless devices such as Machine to Machine (M2M) devices,also denoted Machine Type Communication (MTC) devices. In this example,four ANs are exemplified as APs, i.e., AP 610, AP 620, AP 630, and AP640, and two ANs are exemplified as UEs, i.e., UE 650 and UE 660.Furthermore, each AN can be regarded as either a transmitting node or areceiving node in different radio links. For example, in a link on whichAP 610 transmits data to UE 650, AP 610 is a transmitting node, and UE650 is a receiving node. In contrast, in a link on which AP 610 receivesdata from UE 650, AP 610 is a receiving node, and UE 650 is atransmitting node. To put it differently, a radio node or an AN may beeither a client radio node or a serving radio node, depending on itsrole. For example, if a radio node is UE 660 as shown in FIG. 6, AP 620serves its serving radio node. It is also possible that a UE may play arole of a serving radio node when the UE serves as a hot point andserves other UEs. In this case, the serving radio node is the UE, andclient radio nodes may be other UEs served by the UE.

FIG. 7 shows a flowchart of a method 700 performed in a control node,e.g., CCU 600 in FIG. 6, according to embodiments of the presentdisclosure. To be specific, the method 700 is used for implementing ADSSat network side.

At step S710, the control node determines sounding and sensing relatedparameters for a link, e.g., a radio link between AP 610 and UE 650 asshown in FIG. 6. The determined sounding and sensing related parametersinclude dedicated sounding and sensing related parameters for the linkand common sounding and sensing related parameters for all linkscontrolled by the control node. The common sounding and sensing relatedparameters include a sounding and sensing period and a sounding andsensing interval (i.e., a duration for sounding and sensing).

As a feasible implementation, the control node may determine thesounding and sensing related parameters upon receipt of a setup requestfor the link from, e.g., either end of the link, e.g., AP 610 or UE 650,etc.

At step S720, the control node transmits the determined sounding andsensing related parameters to a transmitting node and a receiving nodeof the link. For example, the transmitting node is AP 610 and thereceiving node is UE 650, as shown in FIG. 6.

In an implementation, the common sounding and sensing related parametersmay further include: a rule for the receiving node reporting its sensingresult to the control node.

In another implementation, the dedicated sounding and sensing relatedparameters for the link may include a sounding resource parameter forspecifying a sounding resource element for the transmitting nodetransmitting a sounding signal. The specified sounding resource elementis in terms of at least one or more of: time, frequency, and code.

In another implementation, the method 700 may further include thefollowing steps (not shown) of: receiving one or more sensing resultsfrom all receiving nodes of all links under control of the control node;determining a DLIM based on the received one or more sensing results;and determining a resource allocation scheme or a resource allocationstrategy for data transmission in all links controlled by the controlnode based on the determined DLIM.

One major advantage with the method 700 is receiving nodes of all linkpairs may be in a directional sensing state when the transmitting nodesof their neighboring links are sending directional sounding signals.This enables one link to identify all interfering links and measure theinterference level from these interfering links, based on which thenetwork can efficiently improve spatial reuse of frequency resourceswhile avoiding and/or controlling collisions among different links.

FIG. 8 illustrates a general sounding and sensing resource allocationstructure according to embodiments of the present disclosure.

As shown in FIG. 8, Directional Sounding and Sensing Period (DSSP)denotes a sounding and sensing period, and Directional Sounding andSensing Interval (DSSI) denotes a sounding and sensing interval, i.e., awindow/a duration for sounding and sensing. The DSSP and DSSI are commonsounding and sensing related parameters for all links controlled by thecontrol node, and may be determined by the control node.

The DSSP and DSSI are mainly in terms of time domain. For example, theDSSP and DSSI both refer to time windows. In this case, a transmittingnode of each link may transmit a sounding signal to a receiving node ofthe link in a direction of the link during a time window defined by theDSSI, and the receiving node senses all sounding signals in a direct ofthe link during the same time window. Thereby, inter-link interferences,e.g., DL-DL interference between link 5 and link 6 as shown in FIG. 5,can be sensed in an efficient manner.

Optionally, the DSSP and DSSI may be further in terms of frequencydomain. For example, the DSSI may further define one or more sub-bandsto be used by the transmitting node/the receiving node of the link.

Within the DSSI, there are a number of sounding and sensing resourceelements, some of which are allocated to a link for transmitting asounding signal by means of dedicated sounding and sensing relatedparameters and thus are called as Sounding Resource Units (SRUs). Onesounding and sensing resource element may be defined in terms of atleast one or more of: time, frequency, and code. For example, onesounding and sensing resource element may be defined as onetime-frequency resource unit plus an orthogonal sequence. This meansthat multiple sounding signals may be multiplexed over onetime-frequency unit by using orthogonal sequences.

In practice, the DSSI length may be determined based on the link densityin the network and the DSSP length may be short enough to track theTX/RX beam change of link pairs, including both TX/RX direction changeand TX power change.

An exemplary DLIM may be described by referring to FIG. 5. As shown inFIG. 5, the DLIM can indicate the received sounding signal power fromthe transmitter of each link (Link i, e.g., any one of links 1-6 asshown in FIG. 5) and the received sounding signal strengths from otherlinks whose sounding signals are detected by the link (Link i) receiver.

The DLIM may identify whether a transmitter of a first link contributesconsiderable interference to a receiver of a second link. If there isconsiderable interference contributed, the interference level and thecorresponding link identity are included in the DLIM. Relying thesounding signals (SRU) and corresponding signal strengths reported froma receiver, the control node can identify the links and correspondinginterference levels to the receiver.

For example, the DLIM may be updated upon receipt of a new directionalsounding report from a receiver, or upon link setup/link release.

With such DLIM, the present disclosure can enhance the radio resourceallocation (e.g. time, frequency and TX power resource), so that thespatial reuse can be efficiently and sufficiently improved.

FIG. 9 shows a flowchart of a method 900 performed in a receiving nodeof a link, such as a radio link between AP 610 and UE 650 as shown inFIG. 6, according to embodiments of the present disclosure. To bespecific, the method 900 is used for performing ADSS at receiving side.In this case, the receiving node may be AP 610 or UE 650. Forillustration, UE 650 is taken as the receiving node here, andcorrespondingly AP 610 serves as a corresponding transmitting node forthe receiving node, and vice versa.

At step S910, UE 650 receives sounding and sensing related parametersfor the link from a control node, e.g., the CCU 600 in FIG. 6. Thereceived sounding and sensing related parameters include dedicatedsounding and sensing related parameters for the link and common soundingand sensing related parameters for all links controlled by the controlnode. The common sounding and sensing related parameters include asounding and sensing period and a sounding and sensing interval.

At step S920, UE 650 senses all sounding signals in a direction of thelink based on the received sounding and sensing related parameters.

At step S930, UE 650 reports one or more sensing results to the controlnode.

In an implementation, the common sounding and sensing related parametersfurther include: a rule for UE 650 reporting the one or more sensingresults to the control node.

During the sounding interval, all receiving nodes shall be in blindlymonitoring state in its link direction. Each receiving node shall targetits RX beam in an incoming direction of its link. In order to leave someroom for the RX beam adjustment during one sounding period, the RX beamfor directional sensing could be wider than the RX beam for actual datareceiving.

Via blind detection, the receiving node may determine information on SRUof the detected sounding signals. This information shall be reported tothe control node for possible interfering transmitter identification.Moreover, the receiving node may further measure the strength of eachdetected sounding signal. This measurement result shall be reported tothe CCU to derive the DLIM, which can be used to determine the maximumallowed TX power for a transmitter or interference coordination patternin order to control the interference.

FIG. 10 illustrates an example sensing resource allocation structureaccording to embodiments of the present disclosure. As shown in FIG. 10,each receiving node may sense all possible sounding signals in its linkdirection over all SRUs during the DSSI.

One major advantage with the method 900 is that the receiving node cansense all sounding signals in a direction of the link in a time windowduring which the transmitting nodes of the neighboring links aretransmitting sounding signals. When the method 900 is applied in twoneighboring links, interference between these two links can be sensed inan efficient manner.

FIG. 11 shows a flowchart of a method 1100 performed in a transmittingnode of a link, such as a radio link between AP 610 and UE 650 as shownin FIG. 6, according to embodiments of the present disclosure. To bespecific, the method 900 is used for performing ADSS at transmittingside. In this case, the transmitting node may be AP 610 or UE 650. Forillustration, AP 610 is taken as the transmitting node here, andcorrespondingly UE 650 serves as a corresponding receiving node for thetransmitting node, and vice versa.

At step S1110, AP 610 receives sounding and sensing related parametersfor the link from a control node, e.g., the CCU 600 as shown in FIG. 6.The received sounding and sensing related parameters include dedicatedsounding and sensing related parameters for the link and common soundingand sensing related parameters for all links controlled by the controlnode. The common sounding and sensing related parameters include asounding and sensing period and a sounding and sensing interval, e.g.,DSSP and DSSI as shown in FIG. 8.

At step S1120, AP 610 transmits a sounding signal in a direction of thelink based on the sounding and sensing related parameters.

In an implementation, the dedicated sounding and sensing relatedparameters for the link include a sounding resource parameter forspecifying a sounding resource element for the transmitting nodetransmitting the sounding signal. The specified resource unit is interms of at least one or more of: time, frequency and code.

FIG. 12 illustrates an example sounding resource allocation structureaccording to embodiments of the present disclosure.

As shown in FIG. 12, each transmitting node may be allocated with oneSRU, and there are totally M transmitters controlled by the controlnode, e.g., the CCU 600 as shown in FIG. 6. Optionally, each SRU may bealso defined in terms of frequency. For example, each SRU may occupy onesub-band.

One major advantage with the method 1100 is that the transmitting nodecan transmit a sounding signal in a direction of the link in a timewindow during which the receiving nodes of itself and its neighboringlinks are sensing the sounding signal. When the method 1100 is appliedin two neighboring links, interference between these two links can besensed in an efficient manner.

In practice, one AN may serve multiple links (including access linkand/or backhaul link), and act as transmitter and/or receiver. As one ANcan be only in either TX or RX state no matter how many TX RF chains orRX RF chains it has. Due to this, when the AN is in TX state as atransmitter, it may miss monitoring of some SRUs during each DSSI asreceiver for other links. That is, there is deafness problem in ADSS incase one node serves as both transmitter and receiver for differentlinks. Moreover, for each AN which serves a receiver for a link, thereshould be one RX RF chain targeting in the link direction during eachDSSI. When the number of served receiving links by one AN is larger thanthe number of RX RF chains of this AN, this AN cannot simultaneouslyprocess directional sensing for all served receiving links for which theAN serves as receivers during one DSSI due to lack of RX RF chains.

Aiming to such issues, the present disclosure further proposes to set asounding and sensing related configuration for a radio node undercontrol of one CCU according to network deployment of radio nodes undercontrol of the CCU. To be specific, the present disclosure proposes toconfigure neighboring radio nodes under control of one CCU withdifferent sounding and sensing related configurations.

First of all, a definition of Directional Sounding and Sensing Windows(DSSW) is introduced. Each DSSI as shown in e.g., FIG. 8 may be dividedinto one or more (preferably two or more in the present disclosure)DSSWs. Each DSSW may have a same or different number of sounding andsensing resource elements (e.g., each sounding and sensing resourceelement is indicated by the smallest resource grid in FIG. 8), which maybe consecutive or non-consecutive.

FIG. 13 illustrates three exemplary divisions of DSSI into DSSWsaccording to the present disclosure. In these three examples, a DSSI isdivided into three DSSWs, i.e., DSSW0, DSSW1 and DSSW2. It would beappreciated that a DSSI may be also divided into more than or less thanthree DSSWs.

As illustrated in the upper and middle parts of FIG. 13, each DSSW is ofan equal size, i.e., sounding and sensing resource elements in foursub-bands and two sub-frames. The difference between the upper part andthe middle part lies in that sounding and sensing resource elements inthe former are non-consecutive, and those in the latter are consecutive.In the lower part of FIG. 13, each DSSW has a different number ofsounding and sensing resource elements (i.e., an unequal size ofsounding and sensing resource elements). Although each DSSW asillustrated in FIG. 13 is formed of sounding and sensing resourceelements on four sub-bands, it should be understood that a DSSW may beformed of any number of sounding and sensing resource elements as shownin FIG. 8. Hence, each DSSW per DSSI may be composed by equal/unequalsizes of consecutive/non-consecutive sounding and sensing resourceelements.

According to the present disclosure, at least one DSSW of a DSSI may beallocated to one AN as directional sounding signal transmission window(referred to as Transmission DSSW, i.e., TDSSW), and the rest DSSWs maybe allocated to all of the AN's neighboring ANs as Reception DSSW(RDSSW). In other words, the present disclosure proposes to configureneighboring ANs with different DSSI configurations (DSSI patterns), eachof which is formed of at least one TDSSW and at least one RDSSW.

FIG. 14 shows three exemplary DSSI configurations according to thepresent disclosure. As illustrated, there are three DSSI configurations,i.e., Configuration 0, Configuration 1 and Configuration 2, which can beallocated to three neighboring ANs, respectively. In each configuration,a DSSI is divided into three DSSWs, including one TDSSW and two RDSSWs.This is for illustration, and it would be appreciated that otherappropriate configurations may be applicable.

As shown in FIG. 14, TDSSWs of Configurations 0, 1 and 2 are orthogonalto each other. That is, each sounding resource element involved in TDSSWof Configuration 0 is orthogonal to each sounding resource elementinvolved in TDSSW of Configuration 1 or 2. The “orthogonal” here mayrefer to either time domain or frequency domain. For example, TDSSWs ofConfigurations 0, 1 and 2 may occur in separate subframes, but occupythe same sub-bands. Alternatively, TDSSWs of Configurations 0, 1 and 2may occur in separate sub-bands, but occupy the same subframes.

FIG. 15 illustrates two exemplary network deployments under control of aCCU according to the present disclosure. According to the presentdisclosure, the CCU may determine a DSSI configuration for each AN undercontrol of the CCU, and the AN in turn allocates sounding and sensingresource elements indicated by respective DSSI configuration to eachlink served by the AN.

It is assumed that each AN covers a hexagonal area. In the left part ofFIG. 15, there are 3 different DSSI configurations (e.g., Configurations0, 1 and 2 as shown in FIG. 14), and each AN can be configured with adifferent DSSI configuration than its neighboring ANs. Taking an ANcovering an hexagonal area of FIG. 15 (denoted as AN 1501) as anexample, Configuration 2 as shown in FIG. 14 is allocated to the AN,while its neighboring ANs are allocated with either Configuration 0 orConfiguration 1. In this way, when AN 1501 is in TX state, all linkreceivers of its neighboring ANs are all in RX state.

In the right part of FIG. 15, there are 7 different DSSI configurationsand each AN can be allocated with a different DSSI configuration thaneven more neighboring ANs. For instance, an AN with the shaded area maybe allocated with DSSI configuration 4, while its neighboring ANs withhexagonal areas marked by two dotted cycles are allocated with otherDSSI configurations.

It would be appreciated that any other appropriate network deploymentsother than those as shown in FIG. 15 may be applicable to the presentdisclosure.

FIG. 16 shows a flowchart of a method 1600 used in a serving radio node,e.g., AP2 in FIG. 5, according to embodiments of the present disclosure.The serving radio node serves one or more client radio nodes which areconnected to the serving radio node via one or more radio links, in acoverage area neighboring to one or more coverage areas served by one ormore neighboring radio nodes in a wireless communication network such asa MMW RAT network. For example, AP 2 serves UE 2 and UE 5, UE 2 isconnected to AP 2 via link pair 2, and UE 5 is connected to AP 2 vialink pair 5. In this example, AP1, AP3 and AP4 may be neighboring radionodes of AP2.

The method 1600 includes step S1610, at which the serving radio nodereceives, from a control node (e.g., the CCU in FIG. 5) controlling theserving radio node, a sounding and sensing related configuration for theserving radio node. For example, the sounding and sensing relatedconfiguration may be DSSI configurations as shown in FIG. 14. Eachsounding resource element (i.e., SRU as shown in FIG. 8) indicated bythe sounding and sensing related configuration is orthogonal to eachsounding resource element indicated by a sounding and sensing relatedconfiguration for each neighboring radio node.

In an implementation, the received sounding and sensing relatedconfiguration indicates two or more sounding and sensing windows persounding and sensing duration (i.e. DSSI), one or more sounding andsensing windows of which are configured as sensing windows for sensingby the serving radio node, and the remaining sounding and sensingwindows of which are configured as sounding windows for sounding by theserving radio node.

The received sounding and sensing related configuration for the servingradio node may indicate two or more DSSWs per DSSI, as shown in FIG. 13.For example, the received sounding and sensing related configuration forthe serving radio node may be Configuration 0 in FIG. 14, and thesounding and sensing related configuration for each neighboring radionode may be Configuration 1 or Configuration 2.

As an example of the implementation, the sounding windows for theserving radio node correspond, in time domain, to sensing windows foreach neighboring radio node. In this way, when the serving radio node istransmitting a sounding signal in the sounding windows, each neighboringradio node should be sensing the sounding signal in the sensing windows.That is, when an AN is in TX state during DSSI, its neighboring linkreceivers are all in RX state.

As another example of the implementation, each sounding and sensingwindow has a same or different number of sounding and sensing resourceelements, e.g., as shown in FIG. 13.

As a further example of the implementation, each sounding and sensingwindow has consecutive or non-consecutive sounding and sensing resourceelements, e.g., as shown in FIG. 13.

The method 1600 further includes step S1620, at which the serving radionode senses, through a RX RF chain of the serving radio node configuredfor each radio link of the one or more radio links, all sounding signalsin a direction of the radio link based on the received sounding andsensing related configuration.

In an implementation, the sensing at step S1620 may be performed in allsensing resource elements indicated by the received sounding and sensingrelated configuration. Alternatively, the sensing may be furtherperformed in a part or all sounding resource elements indicated by thereceived sounding and sensing related configuration.

Optionally, the method 1600 may further include step S1630. At stepS1630, the serving radio node allocates one or more sounding resourceelements indicated by the received sounding and sensing relatedconfiguration, to the one or more radio links.

When the number of RX RF chains of the serving radio node is smallerthan the number of all radio links for which the serving node serves asreceivers, it is not possible to process directional sensing for allthese links simultaneously in each DSSI.

In this case, the method 1600 may optionally include two additionalsteps of: adjusting a sensing period for each radio link of the one ormore radio links based on the received sounding and sensing relatedconfiguration and one or more predefined parameters; and sensing,through a RX RF chain of the serving radio node configured for eachradio link of the one or more radio links, all sounding signals in adirection of the radio link, based on the adjusted sensing period.

For example, the serving radio node may process directional sensing forsome links every n-th (n is an integer and n>1) DSSI instead of eachDSSI. That is, a sensing period for each of some links may be adjustedto be larger than one DSSP. Such links may be referred to as slowdirectional sensing links herein. However, the transmission of thedirectional sounding signal for all links can still be processed in eachDSSI so that one or more neighboring links can monitor the interferencesituation. As a consequence, the slow directional sensing links areslower to follow the interference situation, but each link which carriesthe directional sounding can monitor the whole interference situation.The full DLIM can still be achieved at the cost that the experiencedinterferences of the slow directional sensing links are updated with alonger cycle.

FIG. 17 illustrates an exemplary DSSI pattern according to embodimentsof the present disclosure. It is assumed that the serving radio node hastwo RX RF chains, and there are three receiving links served by theserving radio node.

As shown in FIG. 17, the serving radio node may process directionalsensing for the 1st receiving link (Link 0) every DSSI and every otherDSSI for 2nd and 3rd links (Link 1 and 2). That is, sensing periods forLinks 0, 1 and 2 are adjusted to be one DSSP, two DSSPs and two DSSPs,respectively. In this case, Link 0 may be referred to as regulardirectional sensing link while Link 1 and 2 may be referred to as slowdirectional sensing link.

When the number of receiving links by an AN decreases, the AN may adjusta slow directional sensing links to be a regular directional sensinglink (i.e., directional sensing is processed every DSSI for the link).

According to some embodiments of the present disclosure, the one or morepredefined parameters may include at least one of: a link radio quality;a link rate; or a link traffic priority.

As an example, the slow directional sensing links may be selected basedon a link radio quality. For example, a link with a better radioquality, which can endure a higher interference, may be selected withrelatively higher priority. Assume there are two neighboring links, andone link has a better radio link than the other link. In this case, thelink with a better radio quality may be selected as a slow directionalsensing link with a relatively higher priority, and thereby this linkwould be sensed less frequently than the other link, i.e., at a largerperiod.

As another example, the slow directional sensing links may be selectedbased on a link rate. For example, a link with a low required rate maybe selected with relatively high priority.

As a yet another example, the slow directional sensing links may beselected based on a link traffic priority. For example, a link with alower traffic priority may be selected with relatively higher priority.

FIG. 18 shows a flowchart of a method 1800 used in a serving radio nodeaccording to embodiments of the present disclosure. The method 1800 is afeasible variant of the method 1600.

At step S1810, the serving radio node receives, from a control node(e.g., the CCU in FIG. 5) controlling the serving radio node, a soundingand sensing related configuration for the serving radio node. Thesounding and sensing related configuration for the serving radio nodemay be determined by the control node as required, e.g., according tothe detailed network deployment or radio environment. For example, thesounding and sensing related configuration for the serving radio nodemay be determined by the control node, in such a manner that eachsounding resource element indicated by the sounding and sensing relatedconfiguration is orthogonal to each sounding resource element indicatedby a sounding and sensing related configuration for each neighboringradio node.

At step S1820, the serving radio node adjusts a sensing period for eachradio link of the one or more selected radio links based on the soundingand sensing related configuration and one or more predefined parameters,when the number of RX RF chains of the serving radio node is smallerthan the number of the one or more radio links for which the servingnode serves as receivers.

According to some embodiments of the present disclosure, the one or morepredefined parameters may include at least one of: a link radio quality;a link rate; or a link traffic priority. For example, a link with abetter radio quality, a lower link rate, or a lower traffic priority maybe selected as a slow directional sensing link with a relatively higherpriority, and thereby such a link would be sensed with a larger period.That is, a sensing period of such a link may be adjusted to be largerthan one DSSP.

At step S1830, the serving radio node senses, through a RX RF chain ofthe serving radio node configured for each radio link of the one or moreradio links, all sounding signals in a direction of the radio link,based on the adjusted sensing period. For example, the received soundingand sensing related configuration here may indicate the exemplary DSSIpattern as shown in FIG. 17.

FIG. 19 shows a flowchart of a method 1900 used in a control node (e.g.,CCU in FIG. 5) controlling a serving radio node (e.g., AP2 in FIG. 5)according to embodiments of the present disclosure. The serving radionode serves one or more client radio nodes which are connected to theserving radio node via one or more radio links, in a coverage areaneighboring to one or more coverage areas served by one or moreneighboring radio nodes in a wireless communication network such as aMMW RAT network. For example, AP 2 serves UE 2 and UE 5. UE 2 isconnected to AP 2 via link pair 2, and UE 5 is connected to AP 2 vialink pair 5. In this example, AP1, AP3 and AP4 may be neighboring radionodes of AP2.

As shown in FIG. 19, the method 1900 includes steps S1910 and S1920. Atstep S1910, the control node determines a sounding and sensing relatedconfiguration for the serving radio node. The sounding resource elementindicated by the sounding and sensing related configuration for theserving radio node is orthogonal to each sounding resource elementindicated by a sounding and sensing related configuration for eachneighboring radio node.

In an implementation, the determined sounding and sensing relatedconfiguration indicates two or more sounding and sensing windows persounding and sensing duration, one or more sounding and sensing windowsof which are configured as sensing windows for sensing by the servingradio node, and the remaining sounding and sensing windows of which areconfigured as sounding windows for sounding by the serving radio node.

For example, the control node may determine the sounding and sensingrelated configuration based on the network deployment. For example, thecontrol node may allocate Configuration 2 to AN 1501 while Configuration0 or Configuration 1 to AN 1501's neighboring ANs.

The determined sounding and sensing related configuration for theserving radio node may indicate two or more DSSWs per DSSI, as shown inFIG. 13. For example, the determined sounding and sensing relatedconfiguration for the serving radio node may be Configuration 0 in FIG.14, and the sounding and sensing related configuration for eachneighboring radio node may be Configuration 1 or Configuration 2.

As an example of the implementation, the sounding windows for theserving radio node correspond, in time domain, to sensing windows foreach neighboring radio node. In this way, when the serving radio node istransmitting a sounding signal in the sounding windows, each neighboringradio node should be sensing the sounding signal in the sensing windows.

As another example of the implementation, each sounding and sensingwindow has a same or different number of sounding and sensing resourceelements, e.g., as shown in FIG. 13.

As a further example of the implementation, each sounding and sensingwindow has consecutive or non-consecutive sounding and sensing resourceelements, e.g., as shown in FIG. 13.

At step S1920, the control node transmits the determined sounding andsensing related configuration to the serving radio node. Then, theserving radio node may apply the sounding and sensing relatedconfiguration to each served link.

One major advantage with such a configuration is that when the servingradio node is in TX state, all link receivers of its neighboring ANs areall in RX state. In this way, the deafness problem as illustrated inFIG. 3 can be conquered in an efficient manner.

FIG. 20 is a schematic block diagram of a serving radio node 2000according to the present disclosure. The serving radio node 2000 servesone or more client radio nodes which are connected to the serving radionode via one or more radio links, in a coverage area neighboring to oneor more coverage areas served by one or more neighboring radio nodes ina wireless communication network. For example, the serving radio node2000 may be AP2 as shown in FIG. 5, which serves UE 2 and UE 5. UE 2 isconnected to AP 2 via link pair 2, and UE 5 is connected to AP 2 vialink pair 5. In this example, AP1, AP3 and AP4 may be neighboring radionodes of AP2.

As shown in FIG. 20, the serving radio node 2000 includes a receivingunit 2010, a sensing unit 2020, an allocating unit 2030, and anadjusting unit 2040. The allocating unit 2030 and the adjusting unit2040 are optional.

The receiving unit 2010 is configured to receive, from a control node(e.g., the CCU in FIG. 5) controlling the serving radio node, a soundingand sensing related configuration for the serving radio node. Eachsounding resource element indicated by the sounding and sensing relatedconfiguration is orthogonal to each sounding resource element indicatedby a sounding and sensing related configuration for each neighboringradio node.

In an implementation, the received sounding and sensing relatedconfiguration indicates two or more sounding and sensing windows persounding and sensing duration, one or more sounding and sensing windowsof which are configured as sensing windows for sensing by the servingradio node, and the remaining sounding and sensing windows of which areconfigured as sounding windows for sounding by the serving radio node.

The received sounding and sensing related configuration for the servingradio node may indicate two or more DSSWs per DSSI, as shown in FIG. 13.For example, the received sounding and sensing related configuration forthe serving radio node may be Configuration 0 in FIG. 14, and thesounding and sensing related configuration for each neighboring radionode may be Configuration 1 or Configuration 2.

As an example of the implementation, the sounding windows for theserving radio node correspond, in time domain, to sensing windows foreach neighboring radio node. In this way, when the serving radio node istransmitting a sounding signal in the sounding windows, each neighboringradio node should be sensing the sounding signal in the sensing windows.That is, when an AN is in TX state during DSSI, its neighboring linkreceivers are all in RX state.

As another example of the implementation, each sounding and sensingwindow has a same or different number of sounding and sensing resourceelements, e.g., as shown in FIG. 13.

As a further example of the implementation, each sounding and sensingwindow has consecutive or non-consecutive sounding and sensing resourceelements, e.g., as shown in FIG. 13.

The sensing unit 2020 is configured to sense, through a RX RF chain ofthe serving radio node configured for each radio link of the one or moreradio links, all sounding signals in a direction of the radio link basedon the received sounding and sensing related configuration.

In an implementation, the sensing unit 2020 is configured to perform thesensing in all sensing resource elements indicated by the receivedsounding and sensing related configuration. Alternatively, the sensingunit 2020 is configured to further perform the sensing in a part or allsounding resource elements indicated by the received sounding andsensing related configuration.

The allocating unit 2030 is configured to allocate one or more soundingresource elements indicated by the received sounding and sensing relatedconfiguration, to the one or more radio links.

The adjusting unit 2040 is further configured to adjust a sensing periodfor each radio link of the one or more radio links based on the receivedsounding and sensing related configuration and one or more predefinedparameters, when the number of RX RF chains of the serving radio node issmaller than the number of all radio links for which the serving nodeserves as receivers. In this case, the sensing unit 2020 may be furtherconfigured to sense, through a RX RF chain of the serving radio nodeconfigured for each radio link of the one or more radio links, allsounding signals in a direction of the radio link, based on the adjustedsensing period.

For example, the received sounding and sensing related configurationhere may indicate the exemplary DSSI pattern as shown in FIG. 17.

According to some embodiments of the present disclosure, the one or morepredefined parameters may include at least one of: a link radio quality;a link rate; or a link traffic priority. For example, a sensing periodfor a link with a better radio quality, a lower link rate, or a lowertraffic priority may be adjusted to be larger than one DSSP.

FIG. 21 shows a schematic block diagram of another serving radio node2100 according to the present disclosure. The serving radio node 2100here is a feasible variant of the serving radio node 2000.

As shown in FIG. 21, the serving radio node 2100 includes a receivingunit 2110, an adjusting unit 2120, and a sensing unit 2130. Theadjusting unit 2120 operates like the adjusting unit 2040 in FIG. 20.

The receiving unit 2110 is configured to receive, from a control node(e.g., the CCU in FIG. 5) controlling the serving radio node, a soundingand sensing related configuration for the serving radio node. Thesounding and sensing related configuration for the serving radio nodemay be determined by the control node as required, e.g., according tothe detailed network deployment or radio environment. For example, thesounding and sensing related configuration for the serving radio nodemay be determined by the control node, in such a manner that eachsounding resource element indicated by the sounding and sensing relatedconfiguration is orthogonal to each sounding resource element indicatedby a sounding and sensing related configuration for each neighboringradio node.

The adjusting unit 2120 is configured to adjust a sensing period foreach radio link of the one or more radio links based on the sounding andsensing related configuration and one or more predefined parameters,when the number of RX RF chains of the serving radio node is smallerthan the number of the one or more radio links for which the servingnode serves as receivers.

The sensing unit 2130 is configured to sense, through a RX RF chain ofthe serving radio node configured for each radio link of the one or moreradio links, all sounding signals in a direction of the radio link,based on the adjusted sensing period. For example, the received soundingand sensing related configuration here may indicate the exemplary DSSIpattern as shown in FIG. 17.

According to some embodiments of the present disclosure, the one or morepredefined parameters may include at least one of: a link radio quality;a link rate; or a link traffic priority. For example, a sensing periodfor a link with a better radio quality, a lower link rate, or a lowertraffic priority may be adjusted to be larger than one DSSP.

FIG. 22 is a schematic block diagram of a control node 2200 (e.g., CCUin FIG. 5) controlling a serving radio node (e.g., AP2 in FIG. 5)according to embodiments of the present disclosure. The serving radionode serves one or more client radio nodes which are connected to theserving radio node via one or more radio links, in a coverage areaneighboring to one or more coverage areas served by one or moreneighboring radio nodes in a wireless communication network such as aMMW RAT network. For example, AP 2 serves UE 2 and UE 5. UE 2 isconnected to AP 2 via link pair 2, and UE 5 is connected to AP 2 vialink pair 5. In this example, AP1, AP3 and AP4 may be neighboring radionodes of AP2.

As shown in FIG. 22, the control node 2200 includes a determining unit2210 and a transmitting unit 2220.

The determining unit 2210 is configured to determine a sounding andsensing related configuration for the serving radio node. The soundingresource element indicated by the sounding and sensing relatedconfiguration for the serving radio node is orthogonal to each soundingresource element indicated by a sounding and sensing relatedconfiguration for each neighboring radio node.

In an implementation, the determined sounding and sensing relatedconfiguration indicates two or more sounding and sensing windows persounding and sensing duration, one or more sounding and sensing windowsof which are configured as sensing windows for sensing by the servingradio node, and the remaining sounding and sensing windows of which areconfigured as sounding windows for sounding by the serving radio node.

For example, the control node 2200 may determine the sounding andsensing related configuration based on the network deployment. Forexample, the control node 2200 may allocate Configuration 2 to AN 1501while Configuration 0 or Configuration 1 to AN 1501's neighboring ANs.

The determined sounding and sensing related configuration for theserving radio node may indicate two or more DSSWs per DSSI, as shown inFIG. 13. For example, the determined sounding and sensing relatedconfiguration for the serving radio node may be Configuration 0 in FIG.14, and the sounding and sensing related configuration for eachneighboring radio node may be Configuration 1 or Configuration 2.

As an example of the implementation, the sounding windows for theserving radio node correspond, in time domain, to sensing windows foreach neighboring radio node. In this way, when the serving radio node istransmitting a sounding signal in the sounding windows, each neighboringradio node should be sensing the sounding signal in the sensing windows.

As another example of the implementation, each sounding and sensingwindow has a same or different number of sounding and sensing resourceelements, e.g., as shown in FIG. 13.

As a further example of the implementation, each sounding and sensingwindow has consecutive or non-consecutive sounding and sensing resourceelements, e.g., as shown in FIG. 13.

The transmitting unit 2220 is configured to transmit the determinedsounding and sensing related configuration to the serving radio node.Then, the serving radio node may apply the sounding and sensing relatedconfiguration to each served link.

FIG. 23 schematically shows an embodiment of an arrangement 2300 whichmay be used in the serving radio node 2000, the serving radio node 2100,or the control node 2200 according to the present disclosure.

Comprised in the arrangement 2300 are here a processing unit 2306, e.g.,with a Digital Signal Processor (DSP). The processing unit 2306 may be asingle unit or a plurality of units to perform different actions ofprocedures described herein. The arrangement 2300 may also comprise aninput unit 2302 for receiving signals from other entities, and an outputunit 2304 for providing signal(s) to other entities. The input unit andthe output unit may be arranged as an integrated entity or asillustrated in the example of FIG. 20, FIG. 21 or FIG. 22.

Furthermore, the arrangement 2300 may comprise at least one computerprogram product 2308 in the form of a non-volatile or volatile memory,e.g., an Electrically Erasable Programmable Read-Only Memory (EEPROM), aflash memory and a hard drive. The computer program product 2308comprises a computer program 2310, which comprises code/computerreadable instructions, which when executed by the processing unit 2306in the arrangement 2300 causes the arrangement 2300 and/or the servingradio node or the control node in which it is comprised to perform theactions, e.g., of the procedure described earlier in conjunction withFIG. 16, FIG. 18 or FIG. 19.

The computer program 2310 may be configured as a computer program codestructured in computer program modules 2310A-2310E, 2310F-2310I, or2310J-2310L.

Hence, in an exemplifying embodiment when the arrangement 2300 is usedin the serving radio node 2000, the code in the computer program of thearrangement 2300 includes a receiving module 2310A, for receiving, froma control node controlling the serving radio node, a sounding andsensing related configuration for the serving radio node. Each soundingresource element indicated by the sounding and sensing relatedconfiguration is orthogonal to each sounding resource element indicatedby a sounding and sensing related configuration for each neighboringradio node. The code in the computer program 2310 further includes asensing module 2310B, for sensing, through a RX RF chain of the servingradio node configured for each radio link of the one or more radiolinks, all sounding signals in a direction of the radio link based onthe received sounding and sensing related configuration. Optionally, thecode in the computer program 2310 further includes an allocating module2310C, for allocating one or more sounding and sensing resource elementsindicated by the received sounding and sensing related configuration, tothe one or more radio links. Optionally, the code in the computerprogram 2310 further includes an adjusting module 2310D, for adjusting asensing period for each radio link of the one or more radio links basedon the received sounding and sensing related configuration and one ormore predefined parameters, when the number of RX RF chains of theserving radio node is smaller than the number of all radio links forwhich the serving node serves as receivers. The code in the computerprogram 2310 may comprise further modules, illustrated as module 2310E,e.g. for controlling and performing other related procedures associatedwith the serving radio node's operations. For example, when the servingradio node is a BS, then the module 2310E may control and perform otherrelated procedures associated with the BS's operations.

In another exemplifying embodiment when the arrangement 2300 is used inthe serving radio node 2100, the code in the computer program of thearrangement 2300 includes a receiving module 2310F, for receiving, froma control node controlling the serving radio node, a sounding andsensing related configuration for the serving radio node. The code inthe computer program further includes an adjusting module 2310G, foradjusting a sensing period for each radio link of the one or more radiolinks based on the sounding and sensing related configuration and one ormore predefined parameters, when the number of RX RF chains of theserving radio node is smaller than the number of the one or more radiolinks for which the serving node serves as receivers. The code in thecomputer program further includes a sensing unit 2310H, for sensing,through a RX RF chain of the serving radio node configured for eachradio link of the one or more radio links, all sounding signals in adirection of the radio link, based on the adjusted sensing period. Thecode in the computer program 2310 may comprise further modules,illustrated as module 2310I, e.g. for controlling and performing otherrelated procedures associated with the serving radio node's operations.For example, when the serving radio node is a BS, then the module 2310Imay control and perform other related procedures associated with theBS's operations.

In another exemplifying embodiment when the arrangement 2300 is used inthe control node 2200, the code in the computer program of thearrangement 2300 includes a determining module 2310J, for determining asounding and sensing related configuration for the serving radio node.The sounding resource element indicated by the sounding and sensingrelated configuration for the serving radio node is orthogonal to eachsounding resource element indicated by a sounding and sensing relatedconfiguration for each neighboring radio node. The code in the computerprogram further includes a transmitting module 2310K, for transmittingthe determined sounding and sensing related configuration to the servingradio node. The code in the computer program 2310 may comprise furthermodules, illustrated as module 2310L, e.g. for controlling andperforming other related procedures associated with the control node'soperations.

The computer program modules could essentially perform the actions ofthe flow illustrated in FIG. 16, to emulate the serving radio node 2000,or the actions of the flow illustrated in FIG. 18, to emulate theserving radio node 2100, or the actions of the flow illustrated in FIG.19, to emulate the control node 2200. In other words, when the differentcomputer program modules are executed in the processing unit 2306, theymay correspond, e.g., to the units 2010-2040 of FIG. 20, or to the units2110-2130 of FIG. 21, or to the units 2210-2220 of FIG. 22.

Although the code means in the embodiments disclosed above inconjunction with FIG. 23 are implemented as computer program moduleswhich when executed in the processing unit causes the arrangement toperform the actions described above in conjunction with the figuresmentioned above, at least one of the code means may in alternativeembodiments be implemented at least partly as hardware circuits.

The processor may be a single CPU (Central processing unit), but couldalso comprise two or more processing units. For example, the processormay include general purpose microprocessors; instruction set processorsand/or related chips sets and/or special purpose microprocessors such asApplication Specific Integrated Circuit (ASICs). The processor may alsocomprise board memory for caching purposes. The computer program may becarried by a computer program product connected to the processor. Thecomputer program product may comprise a computer readable medium onwhich the computer program is stored. For example, the computer programproduct may be a flash memory, a Random-access memory (RAM), a Read-OnlyMemory (ROM), or an EEPROM, and the computer program modules describedabove could in alternative embodiments be distributed on differentcomputer program products in the form of memories within the servingradio node or the control node.

The present disclosure is described above with reference to theembodiments thereof. However, those embodiments are provided just forillustrative purpose, rather than limiting the present disclosure. Thescope of the disclosure is defined by the attached claims as well asequivalents thereof. Those skilled in the art can make variousalternations and modifications without departing from the scope of thedisclosure, which all fall into the scope of the disclosure.

What is claimed is:
 1. A method used in a serving radio node, whereinthe serving radio node serves one or more client radio nodes which areconnected to the serving radio node via one or more radio links, in acoverage area neighboring to one or more coverage areas served by one ormore neighboring radio nodes in a wireless communication network, themethod comprising: receiving, from a control node controlling theserving radio node, a sounding and sensing related configuration for theserving radio node; adjusting a sensing period for each radio link ofthe one or more radio links based on the sounding and sensing relatedconfiguration and one or more predefined parameters, when a number ofReceiver (RX) Radio Frequency (RF) chains of the serving radio node issmaller than a number of the one or more radio links for which theserving radio node serves as receivers; and sensing, through a RX RFchain of the serving radio node configured for each radio link of theone or more radio links, all sounding signals in a direction of theradio link, based on the adjusted sensing period.
 2. The methodaccording to claim 1, wherein the one or more predefined parametersinclude a link radio quality.
 3. The method according to claim 1,wherein the one or more predefined parameters include a link rate. 4.The method according to claim 1, wherein the one or more predefinedparameters include a link traffic priority.
 5. The method according toclaim 1, wherein the adjusting further adjusts a sensing period of oneof the radio links to be different from another one of the radio links.6. The method according to claim 1, wherein the adjusting furtheradjusts a sensing period of at least one of the radio links to be largerthan one Directional Sounding and Sensing Period (DSSP) configured forthe radio links.
 7. The method according to claim 6, further comprisingassigning the sensing period larger than one DSSP to a radio link havinghigher radio quality than another radio link.
 8. The method according toclaim 6, further comprising assigning the sensing period larger than oneDSSP to a radio link having lower required link rate than another radiolink.
 9. The method according to claim 6, further comprising assigningthe sensing period larger than one DSSP to a radio link having lowertraffic priority than another radio link.
 10. A serving radio node,which serves one or more client radio nodes which are connected to theserving radio node via one or more radio links, in a coverage areaneighboring to one or more coverage areas served by one or moreneighboring radio nodes in a wireless communication network, the servingradio node comprising: a processor; and a memory containing instructionswhich, when executed by the processor, instruct the serving radio nodeto perform operations to: receive, from a control node controlling theserving radio node, a sounding and sensing related configuration for theserving radio node; adjust a sensing period for each radio link of theone or more radio links based on the sounding and sensing relatedconfiguration and one or more predefined parameters, when a number ofReceiver (RX) Radio Frequency (RF) chains of the serving radio node issmaller than a number of the one or more radio links for which theserving radio node serves as receivers; and sense, through a RX RF chainof the serving radio node configured for each radio link of the one ormore radio links, all sounding signals in a direction of the radio link,based on the adjusted sensing period.
 11. The serving radio nodeaccording to claim 10, wherein the one or more predefined parametersinclude a link radio quality.
 12. The serving radio node according toclaim 10, wherein the one or more predefined parameters include a linkrate.
 13. The serving radio node according to claim 10, wherein the oneor more predefined parameters include a link traffic priority.
 14. Theserving radio node according to claim 10, wherein when performingoperations to adjust the sensing period, the serving radio node furtheradjusts a sensing period of one of the radio links to be different fromanother one of the radio links.
 15. The serving radio node according toclaim 10, wherein when performing operations to adjust the sensingperiod, the serving radio node further adjusts a sensing period of atleast one of the radio links to be larger than one Directional Soundingand Sensing Period (DSSP) configured for the radio links.
 16. Theserving radio node according to claim 15, wherein the instructionsfurther instruct the serving radio node to assign the sensing periodlarger than one DSSP to a radio link having higher radio quality thananother radio link.
 17. The serving radio node according to claim 15,wherein the instructions further instruct the serving radio node toassign the sensing period larger than one DSSP to a radio link havinglower required link rate than another radio link.
 18. The serving radionode according to claim 15, wherein the instructions further instructthe serving radio node to assign the sensing period larger than one DSSPto a radio link having lower traffic priority than another radio link.